<!DOCTYPE html>
<html lang="zh_CN">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

</body>
<script type="text/javascript">
    var string = '   boder-bottom-color ';

    // trim 不会改变原字符串
    console.log('(' + string.trim() + ')', '(' + string + ')');

    string = string.trim();

    console.log('(' + string + ')');

</script>

</html>
